Pope Francis has an unlikely ally in the fight against climate change – activist Naomi Klein. Klein is a harsh critic of modern capitalism, arguing for fundamental economic changes in her book This Changes Everything: Capitalism vs. the Climate to address the problems of a warming planet. She is also secular, along with a growing number of the Pope’s allies on the issue.

According to the Guardian, Naomi Klein will lead a high-level climate change conference for the Vatican along with Ghanaian Cardinal Peter Turkson. In the conference, The People and Planet First: the Imperative to Change Course, Klein and Turkson will focus on the Pope’s recent 200-page encyclical that frames global warming as a moral issue.

The Catholic leader’s strident stance on the climate has made even once devoutly Catholic conservatives, like Rick Santorum and Jeb Bush, question the wisdom of their church. Naomi Klein, on the other hand, has always been hated by conservatives.

By inviting the activist author, Francis is already drawing new criticism from conservative commentators for allowing an outsider to head a church function. Nevertheless, Klein is embracing Francis’ newfound role in the global discussion and believes her invitation is proof he’s ready to follow through.

“The fact that they invited me indicates they’re not backing down from the fight. A lot of people have patted the pope on the head, but said he’s wrong on the economics. I think he’s right on the economics.”

UN General Secretary Ban Ki-moon delivered a keynote speech at another Vatican summit back in April, covering both climate change and poverty.

The subject of Naomi Klein’s conference, the Pope’s environmental encyclical, has garnered widespread support, even in other religions. On Sunday, a multifaith rally marched through the Vatican.

The Guardian reports that rally brought thousands from around the world to thank Francis for unwavering commitment.

Kiran Bali came from the U.K. to represent the Hindu community.

“It’s so clear that the world is at a crucial tipping point due to climate change and it’s so important that faith leaders take action on this important issue. Now is the time to unite, to come together and to really make a difference to protect the Earth from further destruction.”

The demonstrations and conferences along with the encyclical are all preparation for the make-or-break climate change summit in Paris in December. Pope Francis will be there to give his moral guidance, which, according to Naomi Klein, is just what the conversation needs.

“There’s a way in which UN discourse sanitizes the extent to which this is a moral crisis. It cries out for a moral voice.”

Whether Pope Francis, and his newest secular ally Naomi Klein, can force real change in the summit remains to be seen.